{"title":"文件上传","version":"2.1","locale":"zh-hans","docname":"topics/http/file-uploads","url":"/zh-hans/2.1/topics/http/file-uploads/","canonical":"https://djangodocs.dev/zh-hans/2.1/topics/http/file-uploads/","summary":"Django处理文件上传时, 文件最终会位于:attr:request.FILES (想了解更多关于``request`` 对象的信息请阅读 request and response…","html":"

文件上传Link to this heading#

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Django处理文件上传时, 文件最终会位于:attr:request.FILES <django.http.HttpRequest.FILES> (想了解更多关于``request`` 对象的信息请阅读 request and response objects 1) 。本文档主要介绍文件是如何存储在硬盘和内存中的，以及如何定制默认行为。

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简单文件上传Link to this heading#

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考虑使用一个简单的表单，表单中包含一个:class:`~django.forms.FileField`字段:

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forms.py
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Python
from django import forms\n\nclass UploadFileForm(forms.Form):\n    title = forms.CharField(max_length=50)\n    file = forms.FileField()\n
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处理这个表单的视图将通过:attr:request.FILES <django.http.HttpRequest.FILES>`获取到文件数据, attr:`request.FILES <django.http.HttpRequest.FILES>`是包含了表单中每个 :class:`~django.forms.FileField (还有 ImageField, 以及其他:class:~django.forms.FileField 的子类)键值的字典 。所以 `数据可以通过`request.FILES['file']``获取到。

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请注意只有在请求是通过 POST 提交且提交的 <form> 表单有 enctype="multipart/form-data" 属性的时候，request.FILES 才会包含文件数据，否则的话， request.FILES 是空的。

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绝大多数的情况下，你只需要像 binding-uploaded-files`中所述将文件数据从``request` 传入给 表单，示例如下：

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views.py
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Python
from django.http import HttpResponseRedirect\nfrom django.shortcuts import render\nfrom .forms import UploadFileForm\n\n# Imaginary function to handle an uploaded file.\nfrom somewhere import handle_uploaded_file\n\ndef upload_file(request):\n    if request.method == 'POST':\n        form = UploadFileForm(request.POST, request.FILES)\n        if form.is_valid():\n            handle_uploaded_file(request.FILES['file'])\n            return HttpResponseRedirect('/success/url/')\n    else:\n        form = UploadFileForm()\n    return render(request, 'upload.html', {'form': form})\n
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注意我们必须将 request.FILES 传入到表单的\n构造方法中，只有这样文件数据才能绑定到表单中。

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我们通常可能像这样处理上传文件：

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Code
def handle_uploaded_file(f):\n    with open('some/file/name.txt', 'wb+') as destination:\n        for chunk in f.chunks():\n            destination.write(chunk)\n
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使用 UploadedFile.chunks() 而不是 read() 是为了确保即使是大文件又不会将我们系统的内存占满。

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There are a few other methods and attributes available on UploadedFile\nobjects; see UploadedFile for a complete reference.

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通过模型来处理上传的文件Link to this heading#

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If you're saving a file on a Model with a\nFileField, using a ModelForm\nmakes this process much easier. The file object will be saved to the location\nspecified by the upload_to argument of the\ncorresponding FileField when calling\nform.save():

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Code
from django.http import HttpResponseRedirect\nfrom django.shortcuts import render\nfrom .forms import ModelFormWithFileField\n\ndef upload_file(request):\n    if request.method == 'POST':\n        form = ModelFormWithFileField(request.POST, request.FILES)\n        if form.is_valid():\n            # file is saved\n            form.save()\n            return HttpResponseRedirect('/success/url/')\n    else:\n        form = ModelFormWithFileField()\n    return render(request, 'upload.html', {'form': form})\n
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If you are constructing an object manually, you can simply assign the file\nobject from request.FILES to the file\nfield in the model:

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Code
from django.http import HttpResponseRedirect\nfrom django.shortcuts import render\nfrom .forms import UploadFileForm\nfrom .models import ModelWithFileField\n\ndef upload_file(request):\n    if request.method == 'POST':\n        form = UploadFileForm(request.POST, request.FILES)\n        if form.is_valid():\n            instance = ModelWithFileField(file_field=request.FILES['file'])\n            instance.save()\n            return HttpResponseRedirect('/success/url/')\n    else:\n        form = UploadFileForm()\n    return render(request, 'upload.html', {'form': form})\n
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Uploading multiple filesLink to this heading#

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If you want to upload multiple files using one form field, set the multiple\nHTML attribute of field's widget:

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forms.py
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Python
from django import forms\n\nclass FileFieldForm(forms.Form):\n    file_field = forms.FileField(widget=forms.ClearableFileInput(attrs={'multiple': True}))\n
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Then override the post method of your\nFormView subclass to handle multiple file\nuploads:

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views.py
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Python
from django.views.generic.edit import FormView\nfrom .forms import FileFieldForm\n\nclass FileFieldView(FormView):\n    form_class = FileFieldForm\n    template_name = 'upload.html'  # Replace with your template.\n    success_url = '...'  # Replace with your URL or reverse().\n\n    def post(self, request, *args, **kwargs):\n        form_class = self.get_form_class()\n        form = self.get_form(form_class)\n        files = request.FILES.getlist('file_field')\n        if form.is_valid():\n            for f in files:\n                ...  # Do something with each file.\n            return self.form_valid(form)\n        else:\n            return self.form_invalid(form)\n
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Upload HandlersLink to this heading#

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When a user uploads a file, Django passes off the file data to an upload\nhandler -- a small class that handles file data as it gets uploaded. Upload\nhandlers are initially defined in the FILE_UPLOAD_HANDLERS setting,\nwhich defaults to:

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Code
["django.core.files.uploadhandler.MemoryFileUploadHandler",\n "django.core.files.uploadhandler.TemporaryFileUploadHandler"]\n
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Together MemoryFileUploadHandler and\nTemporaryFileUploadHandler provide Django's default file upload\nbehavior of reading small files into memory and large ones onto disk.

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You can write custom handlers that customize how Django handles files. You\ncould, for example, use custom handlers to enforce user-level quotas, compress\ndata on the fly, render progress bars, and even send data to another storage\nlocation directly without storing it locally. See Writing custom upload handlers\nfor details on how you can customize or completely replace upload behavior.

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Where uploaded data is storedLink to this heading#

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Before you save uploaded files, the data needs to be stored somewhere.

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By default, if an uploaded file is smaller than 2.5 megabytes, Django will hold\nthe entire contents of the upload in memory. This means that saving the file\ninvolves only a read from memory and a write to disk and thus is very fast.

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However, if an uploaded file is too large, Django will write the uploaded file\nto a temporary file stored in your system's temporary directory. On a Unix-like\nplatform this means you can expect Django to generate a file called something\nlike /tmp/tmpzfp6I6.upload. If an upload is large enough, you can watch this\nfile grow in size as Django streams the data onto disk.

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These specifics -- 2.5 megabytes; /tmp; etc. -- are simply "reasonable\ndefaults" which can be customized as described in the next section.

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Changing upload handler behaviorLink to this heading#

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There are a few settings which control Django's file upload behavior. See\nFile Upload Settings for details.

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Modifying upload handlers on the flyLink to this heading#

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Sometimes particular views require different upload behavior. In these cases,\nyou can override upload handlers on a per-request basis by modifying\nrequest.upload_handlers. By default, this list will contain the upload\nhandlers given by FILE_UPLOAD_HANDLERS, but you can modify the list\nas you would any other list.

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For instance, suppose you've written a ProgressBarUploadHandler that\nprovides feedback on upload progress to some sort of AJAX widget. You'd add this\nhandler to your upload handlers like this:

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Code
request.upload_handlers.insert(0, ProgressBarUploadHandler(request))\n
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You'd probably want to use list.insert() in this case (instead of\nappend()) because a progress bar handler would need to run before any\nother handlers. Remember, the upload handlers are processed in order.

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If you want to replace the upload handlers completely, you can just assign a new\nlist:

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Code
request.upload_handlers = [ProgressBarUploadHandler(request)]\n
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